Sorry if this has already been asked. I couldn't find the answer. I have a Husqvarna push mower with a Honda GCV160 engine. The Husq owners manual does not mention checking the valve lash as part of the maintenance program. The Honda owners manual states that it should be checked every 100 hours. This mower is about 3 years old and only gets used to trim after mowing with a rider. Is it really necessary to check this that often?